generic-filehandle


Provides a uniform interface for accessing binary data from local files, remote HTTP resources, and Blob data in the browser. Implements a subset of the Node.js v10 promise-based FileHandle API.

Usage

``js
import { LocalFile, RemoteFile, BlobFile } from 'generic-filehandle'

// operate on a local file path
const local = new LocalFile('/some/file/path/file.txt')

// operate on a remote file path
const remote = new RemoteFile('http://somesite.com/file.txt')

// operate on blob objects
const blobfile = new BlobFile(new Blob([some_existing_buffer], { type: 'text/plain' }))

// read slice of file, works on remote files with range request, pre-allocate buffer
const buf = Buffer.alloc(10)
const { bytesRead } = await remote.read(buf, 0, 10, 10)
console.log(buf.toString())

// readFile, returns buffer
const buf = remote.readFile()
`

Important: under node.js, you should supply a fetch function to the RemoteFile constructor

`js
import { RemoteFile } from 'generic-filehandle'
import fetch from 'node-fetch'
const remote = new RemoteFile('http://somesite.com/file.txt', { fetch })
`

API

$3

- buf - a pre-allocated buffer that can contain length bytes
- offset - an offset into the buffer to write into
- length - a length of data to read
- position - the byte offset in the file to read from
- opts - optional Options object

Returns a Promise for the number of bytes read, and the data will be copied
into the Buffer provided in the arguments.

$3

Returns a Promise for a buffer or string containing the contents of the whole file.

$3

Returns a Promise for an object containing as much information about the file as is available. At minimum, the size of the file will be present.

$3

Closes the filehandle.

$3

The Options object for the constructor, read and readFile can contain abort signal
to customize behavior. All entries are optional.

- signal - an AbortSignal that is passed to remote file fetch() API or other file readers
- headers